ASTM E84

ASTM E84 is the Steiner tunnel test method for surface flame spread and smoke. The published method is a 10-minute lab run on a specimen. It is not a WUI listing and not a noncombustible classification. Oregon R327, where adopted, uses an extended E84 or UL 723 run to define ignition-resistant material. An E84 number on a brochure does not replace an OSFM listing or a permit.

Why it matters

Embers and small flames at the wall and at a walking surface are the exposure the WUI codes we cite are trying to slow. Specifiers then reach for “ignition-resistant siding.” That phrase is not a brand. In Oregon it is a 30-minute tunnel definition. A 10-minute interior-finish tunnel result is a different job.

How the Steiner tunnel works

ASTM E84-24 is titled Standard Test Method for Surface Burning Characteristics of Building Materials. The specimen is a nominal 24-foot by 20-inch piece, mounted in the ceiling position, face down to the ignition source. The run is comparative. Flame travel is judged against select-grade red oak and fiber-cement board under the fire exposure the method describes.

The method reports a flame spread index and a smoke developed index. ASTM states there is not necessarily a relationship between those two numbers. The published E84 run is 10 minutes.

ASTM also states what the method does not do. It does not measure heat transmission through the tested surface. It does not, by a flame spread index alone, classify a material as noncombustible. It is not, by itself, a fire-hazard or fire-risk assessment of the product on your lot.

When a user needs a 30-minute duration tunnel test, ASTM E84-24 points to Test Method E2768. That is ASTM’s own split. It is not a listing program.

The paths that use E84

Do not collapse these into one stamp.

1. The method as written. A lab result for a specimen, in that mounting, for 10 minutes. Manufacturer “E84 approved” copy is not a listing.

2. Oregon prescriptive ignition-resistant path, R327 where adopted. R327.2 defines ignition-resistant material as a product designed for exterior exposure that meets the 30-minute tunnel conditions above (amendment PDF). R327 names ASTM E84 or UL 723. UL 723 is the related Steiner-tunnel procedure in that sentence. A UL report is still not an OSFM listing and not a permit.

3. Where R327 uses that definition. Exterior walls (R327.3.3) may use ignition-resistant material as one covering path, alongside noncombustible, heavy timber, log, or an ASTM E2707 wall assembly. The same ignition-resistant covering appears on eaves, projections, and underfloors. Walking surfaces (R327.3.5) include ignition-resistant material that meets R327.2. See siding and decking.

4. California listing path. CWUIC is the live California book as of 1 January 2026. People still search Chapter 7A. OSFM category 8170 is ignition-resistant materials. Category 8140 is exterior wall siding and sheathing. They are not the same bucket. Handbook lines we ingested for 8170, and some 8140 rows, name ASTM E84 with an extended 20-minute run. Listing remains voluntary for most WUI products. Absence from the handbook is not an automatic ban. Presence is not an automatic permit. See OSFM BML.

5. Not a roof class. Class A on this site is ASTM E108 or UL 790 on a roof assembly. See ASTM E108 / UL 790.

Oregon and California are not the same job. Read R327 versus CWUIC.

What people mix up

• Treating ASTM E84 as a WUI listing. E84 is a test method. A listing is a named model at a listing body.

• Treating a 10-minute flame spread index of 25 as Oregon ignition-resistant. R327 extends the run to 30 minutes and adds the progressive-combustion and 10.5-foot flame-front conditions.

• Treating an OSFM 8170 “extended 20-minute” note as Oregon’s 30-minute definition. Nichiha AWP (8170-2029:0005) and TruLog Siding (8170-2399:0001) are 8170 records whose ingested handbook notes name ASTM E84 with an extended 20-minute run. Confirm the live GOVmotus record. Do not import that note into an R327.2 check.

• Treating category 8170 as category 8140. 8170 is ignition-resistant materials. 8140 is exterior wall siding and sheathing. Some cladding models sit in 8170. Anenda AL13 FR B1 (8140-2359:0002) is an 8140 row whose ingested note names ASTM E84 with an extended 20-minute run and “Ignition resistant.” Read the category on the listing.

• Calling an E84 result Class A. Roof class is a different test on a different assembly.

• Calling an E84 result noncombustible. ASTM says a flame spread index by itself does not do that. R327 points noncombustible to ASTM E136.

• Painting a fire coating on wood siding and calling it ignition-resistant. Coatings are not on the R327 wall list. See Findings.

• Assuming an 8110 deck listing includes E84. Trex Transcend (8110-2052:0004) handbook notes on this site say ASTM E84 was not conducted, and that the attached wall covering shall be noncombustible or ignition-resistant. That is a listing condition, not a ban. See decking.

• Reading “OSFM listed” as an Oregon permit. Deschutes County will use the handbook when the product is on the drawings. The authority having jurisdiction still stamps the job.

• Treating IBHS Enhanced noncombustible wall covering as the same as R327 ignition-resistant. IBHS Wildfire Prepared Enhanced is a designation. It is not adopted code.

How to check

Read the adopted code for the lot. If R327 applies and you are claiming ignition-resistant material, the report has to match R327.2: ASTM E84 or UL 723, 30 minutes, flame spread index not more than 25, no significant progressive combustion, flame front not more than 10.5 feet beyond the burner centerline.

If you spec an OSFM listed model, open the product page, then the listing URL. Match the listing ID and the model. Read the duration note. Category 8170 is not a substitute for reading R327. How to read a listing.

Deschutes County says handbook products count only if you show them on the drawings.

On a brochure, a flame spread index without duration, mounting, and the exact standard edition is not enough.

Limits

This page does not host the ASTM text. Buy or read E84 and, if you need the 30-minute tunnel ASTM names, E2768.

This page does not decide what your building official will stamp. It does not make a wall fireproof. It does not rank brands. It does not turn an 8170 table into a shopping list.

A performance path wall in Oregon can be ASTM E2707 instead of an ignition-resistant covering. That is a different test. This page does not cover it.

FireApproved is not a listing body and not an AHJ.

Sources

1. ASTM E84-24 Standard Test Method for Surface Burning Characteristics of Building Materials (ASTM International)
2. 2023 ORSC Section R327 amendment (Oregon Building Codes Division)
3. OSFM Building Materials Listing and WUI handbook (CAL FIRE OSFM)
4. Home hardening and wildfire hazard mitigation (Oregon BCD)
5. Fire Hardening Requirements (R327) (Deschutes County)
6. 2025 California Wildland-Urban Interface Code
7. Wildfire Prepared Home (IBHS)